Proline-rich peptides protective against s. pneumoniae

Abstract

The invention relates to lipopeptides consisting of a peptide chain comprising a parallel coiled-coil domain, a proline-rich peptide antigen, and a lipid moiety, all covalently linked, which aggregate to synthetic virus-like particles. Proline-rich peptide antigens considered contain negatively and positively charged amino acid, and at least 15% of the amino acids are proline. Such synthetic virus-like particles carrying proline-rich antigens derived from pneumococcal proteins are useful as vaccines against infectious diseases caused by Gram-positive bacteria such as Streptococcus pneumoniae.

1 . Lipopeptide building block consisting of
 (1) a peptide chain comprising a parallel coiled-coil domain which, as a self-standing lipid-free peptide, forms a parallel dimeric, trimeric or higher order oligomeric helical bundle,   (2) a proline-rich peptide antigen comprising at least one negatively and at least one positively charged amino acid, and wherein at least 15% of the amino acids are proline, optionally linked to a further antigen, and   (3) a lipid moiety comprising two or three long hydrocarbyl chains,   wherein the peptide chain, the proline-rich peptide antigen and the lipid moiety are covalently linked, either directly or through a linker.   
     
     
         2 . Lipopeptide building block according to  claim 1  wherein the peptide chain comprises between 21 and 200 amino acid residues. 
     
     
         3 . Lipopeptide building block according to  claim 1  wherein the peptide chain comprises a coiled-coil domain consisting of three to eight heptad motifs. 
     
     
         4 . Lipopeptide building block according to  claim 3  wherein in the coiled-coil domain positions a and d in each heptad motif (abcdefg) comprise alpha-amino acids with small to medium-sized hydrophobic side chains and/or aromatic or heteroaromatic side chains, in zero, one or two of all the a and d positions an amino acid with a polar non-charged residue and in zero or one of all the a and d positions an amino acid with a polar cationic residue or an acylated derivative thereof, or with a polar anionic residue, or glycine. 
     
     
         5 . Lipopeptide building block according to  claim 4  wherein
 alpha-amino acids with small to medium-sized hydrophobic side chain are alanine, isoleucine, leucine, methionine and valine; 
 alpha-amino acids with aromatic or heteroaromatic side chain are phenylalanine, tyrosine, tryptophan and histidine; 
 alpha-amino acids with polar non-charged residue are asparagine, cysteine, glutamine, serine and threonine; 
 alpha-amino acids with polar cationic residue are arginine, lysine and histidine; and 
 alpha-amino acids with polar anionic residue are aspartic acid and glutamic acid. 
 
     
     
         6 . Lipopeptide building block according to  claim 1  wherein the proline-rich peptide antigen comprises at least one glutamic acid residue and at least one lysine or arginine residue. 
     
     
         7 . Lipopeptide building block according to  claim 1  wherein the proline-rich peptide antigen is derived from proteins of Streptococci and/or Staphylococci. 
     
     
         8 . Lipopeptide building block according to  claim 1  wherein the proline-rich peptide antigen is derived from proteins PspA and/or PspC. 
     
     
         9 . Lipopeptide building block according to  claim 1  wherein the proline-rich peptide antigen comprises a peptide of SEQ ID NO:27 to 112, and such peptides in which one, two or three amino acids are replaced by other amino acids. 
     
     
         10 . Lipopeptide building block according to  claim 1  wherein the lipid moiety is one of types Z 1  to Z 8   
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are long hydrocarbyl or long hydrocarbyl-C═O and Y is H or COOH, 
       
       
         
           
           
               
               
           
         
         wherein R 1 , R 2  and R 3  are long hydrocarbyl or long hydrocarbyl-C═O or R 1  and R 2  are long hydrocarbyl or long hydrocarbyl-C═O and R 3  is H or acetyl or lower alkyl-C═O, 
       
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are long hydrocarbyl or long hydrocarbyl-C═O and n is 1, 2, 3 or 4, 
       
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are long hydrocarbyl, X is O or NH, and n is 1, 2, 3 or 4, or 
       
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are long hydrocarbyl. 
         and wherein long hydrocarbyl is straight or branched alkyl or alkenyl consisting of between 8 and 25 carbon atoms and optionally one, two or three double bonds in the chain. 
       
     
     
         11 . Lipopeptide building block according to  claim 10  wherein the lipid moiety is di-palmitoyl-S-glycerylcysteinyl of formula Z 3 , wherein R 1  and R 2  are palmitoyl and R 3  is H or acetyl. 
     
     
         12 . Lipopeptide building block according to  claim 1  wherein the peptide chain comprising a parallel coiled coil is linked at one end to the PR peptide antigen and at the other end to the lipid moiety. 
     
     
         13 . Lipopeptide building block according to  claim 12  wherein the peptide chain PC is covalently linked to the lipid moiety LM at or near one terminus of the peptide chain either directly as in
   LM-PC  (1)
 
 or via a linker (L) as in
   LM-L-PC  (2)
 
 
 wherein linker L is selected from 
 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein X is O or NH, m is between 1 and 45 and n is between 1 and 45. 
       
     
     
         14 . Synthetic virus-like particles consisting of helical lipopeptide bundles comprising two, three, four, five, six or seven lipopeptide building blocks according to  claim 1 . 
     
     
         15 . A vaccine comprising a synthetic virus-like particle according to  claim 14 . 
     
     
         16 . A method of vaccination against a disease caused by Gram-negative bacteria wherein an immunogenically effective amount of a synthetic virus-like particle according to  claim 14  is administered to a patient in need thereof.